Immunization + Vaccination MLS 227T

Define “Immunity” and “Immunization”

Immunity - being resistant to disease

Immunization - how immunity is required

What are the 3 types of immunity?

1. Active

2. Passive

3. Adoptive

Active Immunity Definition and Examples + Pros/Cons

Definition - stimulating one’s immune system to mount an adaptive immune response

Examples

• Natural exposure to infection (i.e producing antibodies to an infection)

• Administration of a vaccine

Pros: Induces Long-term protection

Cons: Takes time to develop

Passive Immunity Definition and Examples (+Pros/Cons)

Definition - results in the transfer of antibodies from an immunized host to a nonimmune individual

Examples

• Transfer of mother’s Abs to fetus (IgG - cross placenta) or infant (IgA - breast milk)

• Immunotherapy (I.e. pooled human antibodies for a person w/ immunodeficiency disease)

  1. Standard Human Immune Serum Globulin (HISG) - pooled serum of donors w/ immunity to numerous pathogens

  2. Animal globulin - anti-toxin, anti-venom

  3. Antigen-Specific Immune Globulins (Same as HISG only difference is this is antigen specific)

  4. Monoclonal Antibodies - made by a single clone of B cells directed against specific epitope of antigen

Pro: Provides immediate Immunity

Cons: Immunity is short lived + can induce Type I or III hypersensitivity

Adoptive Immunity Definition, Examples + Pros/Cons

Definition - transfer of cells of the immune system (lymphocytes) from immunized hose to nonimmune individual

Examples

• Car-T cell therapy

• Hematopoietic stem cell transfer to leukemia patients

Pros: Transfer of Cell-mediated Immunity

Cons: Patient’s own immune cells depleated + Possible rejection of allogeneic cells

Vaccine Types and examples

Whole Organism

• Attenuated - Live but weakened version of pathogen

  • Example: Typhoid Fever; Bacillus Calmette Guerin (BCG)

• Inactivated - dead pathogen

  • Example: Polio (specifically Sabin) + Flu + MMR

Subunit (part of the organism)

• Toxoids

  • Ex: Tetanus; Diphtheria

• Polysaccharides

  • Ex: Meningitis; S. Pneumonia

• Purified/Recombinant Proteins

  • Ex: Pertussis (Purified); HepB (recombinant)

What Factors influence Immunogenicity and How?

1. Age (Old people have weaker immune system; vaccines must be age appropriate for safety and efficacy)

2. Immune Status (Immunocompromised pts cant have live vaccines - which are the strongest)

3. Vaccine Composition (as said before, attenuated vaccines are the most immunogenic, subunits are the least)

What are Adjuvants, what do they do and Examples

Adjuvants - Substances that enhance immune response with given together w/ vaccine - result in faster, longer-lasting immune response

They Stimulate the innate immune sys to induce release of cytokines to activate adaptive immune sys

Ex: Aluminum Salts; “Oil-in-water emulsions”; Virosomes; CpG

Define Heard Immunity (General principal) - why is it important

General Principal: If no one is immunized, disease spreads through the population easily. The more immunized people there are, the harder it is for disease through the population

Importance: Heard immunity contains disease spread